Augmented Reality (AR) overlays virtual images (e.g., synthetic images) onto a physical scene (e.g., the user's actual real life surroundings). AR is different from Virtual-Augmented Reality (VAR), which displays a video image of a physical scene with virtual images overlaid thereon.
Traditional AR systems require users to wear head-mount devices (HMD) or near-eye display terminals, which are complicated, heavy, and bulky due to their electronic projectors and displays, electronic circuits, optical accessories (e.g., lenses, beam-splitters, prisms, mirrors, etc.), and power supplies. As such, existing AR systems are cost prohibitive, excessively heavy after prolonged use, and tend to cause stress to the user's eyes, neck, and shoulders.
In general, AR systems comprise a head mount and/or helmet, which straps onto the user's head and over their eyes. Traditional AR helmets include a rear projector unit, a micro-display, and a viewing plane, which is at least partially transparent. The rear projector, which is behind the user's line of vision, projects virtual images onto the micro-display, which is located above the user's line of vision (e.g., near the user's eye brows). The virtual image is then projected from the micro-display onto the viewing plane, which is within the user's line of vision. In order to route the virtual image as described, the AR system uses a complicated optical guiding system comprising beam-splitters, prisms, lenses, mirrors, and other cumbersome optical accessories. Of course, the more sophisticated the virtual image is, the more complicated the optical guiding system becomes.
Further, to facilitate comfort, the viewing plane should be located near the user's eyes. However, to allow the user's eyes to properly focus on the virtual image, the source of the projected image should be located sufficiently far away from the micro-display. Traditional AR systems solve this paradox using additional optical elements and accessories, thereby further increasing the weight, size, bulk, complexity, power consumption, and cost of the AR system.
While AR may be more prolifically used in commercial settings (e.g., product design), users desire AR for recreational and/or personal uses such as overlaying virtual images and virtual messages on a physical scene while reading a book, watching TV, viewing an exhibition (e.g., art), etc. Although users may tolerate complicated and bulky AR systems in commercial settings because an employer requires the bulky system's use, these bulky AR systems impose a barrier toward long term sustainability of the technology, especially for recreational or casual uses.